After reading on the MTBR forum recently that Stumpjumper FSR’s can be converted to 650B wheels, and I had access to a set of 650B from my XC bike and thought I would give it a go. I dropped the fork to check there was no clashing with the frame – no obvious problem. The tyre clearance in the fork crown is tight but no issue. I am yet to check the back wheel as it was a different axle format. If all goes well, this could be my new 650B trail bike. Watch this space.

As a follow up to this thread, now I have rebuild this bike I checked again. The gaps seem smaller now and the front tyre positively rubs when the bike is upside down. Considering the tyres on my 650B wheels are XC based (Schwalbe Nobby Nic and Racing Ralph), I am not willing to go with something with a lower profile just to fit my frame. My Stumpjumper needs masses of grip so I will continue to run 26″ wheels with downhill inspired tyre patterns. It’s a shame but I don’t want to negatively affect the performance of this bike.